The goal of the proposed project is to share characterized adult primary human microglia cells of various passages from normal and diseased human brains with researchers nationally and internationally. High yield and well characterized adult human microglia cultures from our library will allow mechanistic in vitro studies with cells from the same case used in different experimental conditions. Availability of large numbers of cells would also allow initial testing of drugs that can regulate microglial functions and permit isolation of large amounts of RNA and/or protein for transcriptomic or proteomic studies. Microglia have diverse functions in the healthy and diseased brain. A great deal of what has been learned regarding microglia biology is based on in vitro studies the overwhelming majority of which used cells isolated from the rodent brain. However, higher anatomical and functional complexity of the human brain and species differences in microglia response and function make imperative the use of human microglia to ascertain that the results obtained are applicable to man. Investigation of microglia function in the adult brain, in which many inflammatory and anti-inflammatory microglia responses occur, requires use of human microglia from adult brains. Microglia cultured from embryonic human brain show substantial proliferative capacity. However, while methods for isolation of microglia from adult postmortem human brains had been described, they allowed only use of a limited quantity of microglia isolated and cultured from each case due to low levels of proliferation. We have developed a method that allows culturing microglia from adult postmortem human brains to high passage and have found that such cells maintain their phenotype in high passage cultures. We have built a library of primary adult human microglia cells of various passages from young and aged postmortem brains and from brains of individuals with various neurodegenerative disorders. The primary goal of the proposed work is to share human microglia with researchers. The specific aims of the proposed work are: Aim 1 ? Disseminate information regarding availability of characterized adult primary human microglia from brains of normal young, normal aged and brains with various neurodegenerative disorders for research and share such microglia from appropriate passages with researchers nationally and internationally. Aim 2 ? Continue phenotypic characterization of human microglia cultures, including deep sequencing, and additional characterization as requested by recipients. Aim 3 ? Replenish and expand the library by culturing from additional cases and passaging microglia from existing cases. Sharing of primary adult human microglia from various cases and different passages will provide the scientific community with a new and reliable tool for in vitro mechanistic studies of human microglia function in health from childhood to old age, and in diseases of the nervous system.